Plate lockup means for offset or wraparound printing presses



y 4, 1968 H. J. LUEHRS 3,382,799

PLATE LOCKUP MEANS FOR OFFSET OR WRAPAROUND PRINTING PRESSES Filed July 29, 1966 5 Sheets-Sheet 1 I I Q II I W T T I I3 I I E] I I I H -I I\} M I D: T R I I I I E! I a I I I N I Q; A I I QI Q i[I 4 I NVENTOR.

ATTORNEY y 4, 1968 H. J. LUEHRS 3,382,799

PLATE LOCKUP MEANS FOR OFFSET 0R WRAPAROUND PRINTING PRESSES Filed July 29, 1966 5 Sheets-Sheet 2 WW/ YZK V V V/W m b1 j 1 ////////////7 F "x M l3X H- J. LUEHRS May 14, 1968 PLATE LOCKUP MEANS FOR OFFSET OR WRAPAROUND PRINTING PRESSES 5 Sheets-Sheet 5 Filed July 29, 1966 INVENTOR. Hans J. lae/zr's United States Patent 3,382,759 PLATE LOCKUP MEANS FOR OFFSET 0R WRAPAROUND PRINTING PRESSES Hans J. Luehrs, Westerly, KL, assignor to The (Iottrell Company, Westerly, R.I., a corporation of Delaware Filed July 29, 1966, Ser. No. 568,922 Claims. (Cl. 101-4151) ABSTRACT OF THE DISCLOSURE A lockup for wraparound printing plates comprising a single clamp for head and tail sections wherein the clamping force is provided by the reaction of the tensiomng force on the tail of the plate and the centrifugal force acting on the floating clamping member in the cylinder.

This invention relates to plate lockup means for flexible plates such as are normally used in offset or wraparound letterpress printing.

The purpose of this compact plate lockup in comparison with existing more space-requiring lockups 1s to provide improved plate cylinder rigidity, requisite for good printing, in combination with the application of a minimum number of simple components of sufficient physical strength to produce a dependable but low cost lockup mechanism employing standard manufacturing and assembly methods.

An object of the invention is to provide means to secure to and locate a flexible metal printing plate or plates on a plate cylinder wherein the tail end of each plate is subjected to a given tension in a simple manner to automatically take up any elongation of the plate while printmg.

Another object is to provide quick manual plate locking and unlocking means wherein the operator utilizes a suitably attachable lever or pin wrench to rotate the lockup mechanism through a limited arc of approximately 90 only for either the locking or unlocking operation by a single manual motion.

Another object is to provide a compact and simple plate lockup assembly consisting of few components of exceptional strength so arranged as to require a minimum physical space to retain maximum cylinder rigidity.

Another object is to provide a plate lockup wherein a plate is automatically tensioned and its head and tail end sections are held together in a single clamp and wherein the required clamping force is provided by the reaction of the tensioning force on the tail end of the plate and the centrifugal force acting on a floating clamping memher in the rotating cylinder.

A further object is to provide a plate lockup wherein the above and other objects may effectively be attained as will appear from the detailed description of the invention set forth below.

It will be understood that my invention may be used on cylinders adapted for complete or partial wraparound plates and/or for more than one plate across. Since I illustrate herein a complete wraparound plate lockup and the other lockups mentioned require only a duplication of parts, same will not be further illustrated or described in detail.

Broadly, my invention comprises a longitudinally channelled cylinder having plate lockup means located in the channel, said means being self-aligning and subject to torque whereby the plate is tensioned on the cylinder and said tension is automatically maintained and the plate lockup clamping action on the plate assisted by the centrifugal force on the lockup components during the printing operation.

3,382,799 Patented May 14, 1%68 A practical embodiment of my invention is illustrated in the accompanying drawings in which:

FIG. 1 represents a plan view of one end of a cylinder embodying my invention which cylinder is partly broken away to illustrate the several elements;

FIG. 2 is a section taken on the line IIII of FIG. 1 looking in the direction of the arrows and showing the engagement of the torque bar with the internal hexagonal section of the tube or reel;

FIG. 3 is an end view of a partial section taken on the line III-III of FIG. 1 looking in the direction of the arrows;

FIG. 3A is a partial section taken on the line 111A- IlIA of FIG. 1 looking in the direction of the arrows. The reactions of the elements to the tensioning and clamping forces are indicated by arrows.

FIG. 4 is a top plan view of a fragment of the cylinder and bearer of FIG. 3 showing the relative locations of the collar, torque bar, split sleeve and pawl;

FIG. 5 represents a section taken on line VV of FIG. 4 looking in the direction of the arrows;

FIG. 6 is a detail side view of the rotatable collar, rotation of which tensions the plate on the cylinder and releases same as desired; and

FIG. 7 is a view looking in the direction of the arrows VlI-VII on FIG. 6.

Referring to the accompanying drawings, a plate cylinder 16, adapted in the present showing to carry at least one complete wraparound plate 15 is channelled longitudinally and provided with milled out sections, including 17 and 18, to encompass my novel plate lockup mechanism.

This mechanism comprises a self-aligning plate conforming tubular reel member 7, provided with a cut-out section 32 which is adapted to receive the bent trailing edge of flexible plate 15. Said member 7 is provided with a centrally located internal hexagonal section 8 adapted to operatively engage a complementary hexagonal section of a torque bar 3. This center engagement described above is for the purpose of dividing up the torsional deflection of the reel under the load exerted against the plate and to align the tubular reel with, as described below.

The torque bar 3 has an enlarged end section 31, to receive a hex socket wrench for rotating the bar 3 during the initial set-up of the several elements.

Clampcd over hexagonal section 31 0f the bar 3 and over splite sleeve 4 is a collar 2 held thereon by screw bolts 22, 23 seated in taps 26. Said collar 2 has a circumferential bore 21 adapted to receive a pin wrench 1 therein, which wrench may be swung through an arc of approximately to tension plate 15 to or release it from the cylinder 16 as will be more fully described below. The collar 2 is also provided with a cut-out section 28 to receive a pawl 9, and also has stop sections 5 and 6 to engage the milled out portion 18 of cylinder 16 and thereby limit the rotative movement of said collar.

Manually retractable pawl 9 is turnably mounted on stud 29 and is normally biased toward the collar 2 by spring ii seated at one end in the cylinder, its other end engaging the pawl. Stud 29 is provided with a threaded bore 3t! adapted to receive a pipe plug to expand stud 29 for its retention in the bearer.

In the present embodiment, longitudinal filler piece 24 is bolted to cylinder 16 by bolts 25 so as to confine the reel or tube 7 and its associated members in a self-aligning condition with respect to the longitudinal cylinder channel and the tiller piece 24.

It will be understood that the filler piece outer surface matches the cylinder circumference but is so dimensioned as to leave a longitudinal slot across the cylinder circumference to receive the leading and trailing plate edges therein between the filler piece edge and the cylinder channel.

The element '7 is located in the longitudinal cylinder channel so it is free to move therein, the filler piece 24 being secured to the cylinder 16. Torque rod 3, split sleeve 4, and the collar 2 are located and associated as outlined above and the ends of plate introduced into the longitudinal slot, the plate trailing edge being fitted into cutout section 32 of reel 7. A suitable tool such as a hex socket wrench (not shown) is applied to end 31 of rod 3 to set up initial torque prior to clamping collar 2 in its desired location.

The parts being in the above-described relationship collar 2 is clamped over section 31 of bar 3 and split sleeve 4 and the plate 16 is tensioned and maintained under tension on cylinder 15 as follows:

-A pin wrench -1 is inserted in bore 2 1 in collar 2 and swung from right to left (FIG. 3). The said collar is rotated, putting increasing torque on rod 3 which rotates reel 7 due to the engagement of its internal hexagonal section 8 with the complementary section of rod 3. Collar 2 is rotated until pawl 9 falls into cut-out 26, being so urged by spring 19. At this point the plate is tensioned on the cylinder as shown in FIG. 3 and the rod 3 is subjected to a suflicient torsional deflection to impart the required tangential force on reel 7 and to automatically maintain plate tension and take up during the printing operation.

It will be noted that torque bar 3 transmits rotative motion to reel 7 at its central position, through hexagonal section 3 thus distributing equalized torsional loads in both directions through the length of reel 7 to provide the tensional forces on plate 15. The magnitude of these plate tensioning forces produced by the reaction of the torsional deflection of torque bar 3 is predetermined by the relative position of the clamped collar 2 to the reel 7, whereby a sutficient range of automatic takeup is provided to allow for plate elongation during the printing operation.

"Inspection of FIG. 3A will show, in combination with the plate tensioning .forces, other forces acting on the self-aligning reel 7, provided to clamp the head and tail ends of plate 15 to additionally insure that the latter will be held to the rotating cylinder 16. Force designated by 10, resulting from the reacting plate tensioning force 11, plus centrifugal force .12 urge reel 7 centrally into the inverted wedge of approximately 45 formed by the cylinder filler piece 24 and the wall of the cylinder longitudinal cut-out. This serves to clamp plate 15 at 13 with a corresponding reaction at '14. With increasing press speeds, clamping pressure at 13 will increase in proportion to the centrifugal force acting on the reel 7.

It will be noted that tube or reel 7 is self-aligning, as outlined above and is supported in the cylinder longitudinal cut-out at its central portion only (FIG. 2) which allows for alignment of said reel to a biased scarf of a plate while tensioning and clamping said plate.

As clearly shown in FIG. 4, cylinder 16 is milled out only adjacent the bearers 16a (only one bearer being shown) which permits all components except reel 7 to be removed with the bearers on the cylinder and the cylinder in the press.

It should also be noted that no deep drilling is necessary nor is precise alignment of the cylinder aperture in reference to the torque bar hearing within the cylinder bearer.

This application is based on structure similar to that covered by appl'icants United States Patent No. 3,332,- 346, dated July 25, 1967, filed July 29, 1966, but without a spring rod in association with the free floating tensioning means.

Since it is evident that changes may be made in the form, construction and arrangement of the several parts without departing from the spirit and scope of my invention, I do not intend to he limited to the specific embodiment herein shown and described except as set forth in the appended claims.

What I claim is:

'1. In a plate lockup for flexible plates of te wraparound type, the combination including a rotative cylinder having a longitudinal circumferential cut-out section, a central raised portion in said cut-out section, a self-aligning plate tensioning means confined in said cutout section and centrally supported on said raised portion, said plate tensioning means comprising a longitudinal self-aligning member, a second longitudinal member normally engaging the interior of said self-aligning member, a plate edge receiving section in said last-named member, means for imparting rotation to said first member through said second member for releasably tensioning the plate to the cylinder and other means for maintaining the plate in tensioned condition thereon.

2. The combination according to claim 1 in which the cylinder is provided with a filler piece and bearers, the longitudinal circumferential cylinder cut-out section is more widely recessed at its ends and the cylinder ends have longitudinal bores terminating in said cut-out recessed ends whereby the second longitudinal member, the means for imparting rotation and the other means for maintaining the plate under tension may be assembled and disassembled while the cylinder is in the press and without removal of the bearers or the filler piece.

3. In a plate lockup for flexible wraparound plates, a rotative cylinder having a longitudinal circumferential cut-out section, a filler piece removably fixed to the cylinder along one side of said section and a plate tensioning means located in said cut-out section and confined therein by said filler piece, said plate tensioning means comprising a longitudinal self-aligning member, a plate edge receiving slotted section therein, a torque bar located axially internally of said longitudinal self-aligning member and in engagement therewith at its center, a split collar on a bar end section, an adjustable collar over said split collar, means in said adjustable collar adapted to receive a tool for rotating said collar and imparting torque to the torque bar, means on the adjustable collar for maintaining same at plate tensioning position, a pawl engaging said last-named means and means for automatically maintaining plate tension comprising the torque bar subject to residual torque when the pawl is engaged.

4. The combination according to claim 3 in which the plate has leading and trailing edges, the filler piece and cut-out section walls converge and the longitudinal selfaligning member is located for movement radially outwardly toward the converging walls to increase clamping action when the cylinder is rotated.

5. The combination according to claim -1 in which the longitudinal self-aligning member is tubular, the second longitudinal member is a flexible torque bar, said first member has an interior hexagonal section for engagement by said second longitudinal member at a section thereon opposite said central portion of the circumferential cut-out section.

References Cited UNITED STATES PATENTS 2,279,204 4/1942 Neilson 1014 15.1 2,316,935 4/1943 Crafts 101'4l5.1 2,541,254 2/1951 Huck et al fill-415.1 2,900,904 8/1959 Hantscho 1O 1415.1 3,118,600- 1/1964 Saniewski 267- 1 2,730,948 1/1956 Mitchell 101415.l

ROBERT E. PULFREY, Primary Examiner.

F. A. WINANS, Assistant Examiner. 

